There is a continuing desire in the microelectronics industry to increase the circuit density and speed in multilevel integrated circuit devices e.g., memory and logic chips, thereby increasing their performance and reducing their cost. In order to accomplish this goal, there is a desire to reduce the minimum feature size on the chip e.g., circuit linewidth, and also to decrease the dielectric constant of the interposed dielectric material to (i) enable higher propagation speed and (ii) enable closer spacing of circuit lines without increase in crosstalk and capacitive coupling. Further, there is a desire to reduce the dielectric constant of the dielectric materials such as utilized in the back end of the line (BEOL) portion of integrated circuit devices, which contain input/output circuitry, to reduce the requisite drive current and power consumption for the device. A dielectric presently used in integrated circuit devices is silicon dioxide which has a dielectric constant of about 4.0. This material has the requisite mechanical and thermal properties to withstand processing operations and thermal cycling associated with semiconductor manufacturing. However, it is desired that dielectric materials for future integrated circuit devices exhibit a lower dielectric constant than exhibited by silicon dioxide. Lui et al., Material Res. Soc. Symp. Proc. 372 (1995) suggested forming a composite dielectric of ceramic and porous microspheres. The powdered ceramic and hollow microspheres were admixed and sintered at a very high temperature (greater than 900.degree. C.) to form the crystallized composite. However, such high temperatures are unsuitable for some manufacturing processes for integrated circuit devices.
It is therefore an object of the present invention to provide a dielectric material and improved process for making an integrated circuit device.
Other objects and advantages will be apparent from the following disclosure.